Sludge tank and gas producer



Sept. 14 1926.

H. L. THACKWELL SLUDGE TANK AND GAS PRODUCER Filed June 22, 1925 4 Sheets-Sheet 1 J n/0 M701, *1 4. fig 6,41 4% Sept. 14 1926.

H. L. THACKWELL SLUDGE TANK AND GAS PRODUCER 4 Sheets-Sheet 3 Filed June 22, 19 25 INVENTOR 6 4 7220 52/6// BY ATTORNEY Sept. 14 1926.

1,599,731 H. THACKWELL.

SLUDGE TANK AND GAS PRODUCER Filed June 22 1925 4 Sheets-Sheet 4 ATTORNEY UNITED STAT 7 enn 1., THACKWELL, or nannas, rams, assmnon'or one-1mm? r rnnn a.

y JONES, or mnmarnxas.

snnnen mm: m GAS rnonnonn.

Application filed June 22, 1925. Serial No. 88,685.

This invention relates to new and useful improvements in sludge tanks and gas producers.

The invention has to do with that portion of sewage disposal lants wherein the effluent is received an digested, prior to being aerated andclarified.

The object of the invention is to stimulate the bacterialdigestion of sludge by an m- .cre'ased temperature and more vigorous activity of the bacteria.

Another object of the invention is to ob viate odors and to utilize the generated gas for fuel for heating a medium for heating the sludge.

A further object of the invention is to obtain an increase in the total digestion of the sludge, thus requiring less capacity and making for. economical results.

the sludge thus requiring less drying area for such residue.

A still further object of the invention is to retard the upward passage of the mass into the throat of the gas collecting chamber or'hopper, thereby preventing the formation of scum on top of the efliuent in said chamber.

A construction designed to carry out the invention will be hereinafter described together with other features of theinvention.

The invention will be more readily understood from a reading of the following specification and by reference tothe accompanying drawings, in which an'example of .the invention is shown, and wherein:

Fig. 1 is a plan view of a tank constructed in accordance with my invention,

Fig. 2 is a longitudinal vertical sectional view taken on theline 2-2 of Fig. 1,

Fig. 3 is a. transverse vertical sectional view taken on the line 3-3 of Fig. 1,

Fig. 4 is a vertical sectional view of the gas trap,

Fig. 5 .is an enlarged vertical sectional view taken on the line 5-5 of Fig. 3,

Fig. 6 is a detail of the scum screen, and

Fig. 7 is a fragmentary lan view of the disposal plant in which e invention is shown. v

In the drawings the numeral 10 designates a purification tank of the inverted con-' ical type. This tank has a gutter 11 around its upper edge surmounting the upright walls at the upper portion of said tank.

Another object is to reduce the residue of Inclined side walls 12 lead down from the upright walls to a hopper bottom 13. About midway of the walls 12 are longitudinal abutments or ledges 14 having inclined surfaces so as'to prevent lodgement of solids thereon.

Vertical partitions 15 extend longitudinally on each side of the center of the tank and from the bottom of each partition, a septum 16 inclines downwardly. and outwardly so that its lower end overhangs the upper side of the adjacent abutment, but is spaced therefrom. By this arran ement the abut-- ments 14 extend inwardly yond the lower ends of the septums, thereby deflecting uprising gases into the hood formed by the se tums.

ransverse beams 16* extend across the upper open end of the tank. A vertical partition 17 extends verticall at the center of the tank. This partition as an opening 18 in the hop er bottom 13. An infiuent sluice 19 is provided at one end of the tank and weirs 20 are provided at the other end of the tank over which the effluent flows. That portion of the tank confined between the walls 15 constitutes a gas chamber 15; while within the hood defined by the septums 16 is formed a transition chamber. The spaces on each side of the walls 15 and 16 and below the ledges 14 form a sedimentation chamber.

The top of the gas chamber is sealed by transverse flanged metal plates 21 bolted together and constituting a cover. These plates are suitably fastened on top of the walls 15. At the center of the cover a cap 22 is bolted to the plates over on opening 23. Inclined sludge discharge pipes24: are disposed on each side of the partition 17 Each pipe has a four-way fitting 25 at its lower end and includes a four-way connection 26 from which a discharge pipe 27 leads through the adjacent septum and side wall 12 of the tank. The top of each pipe extends into the cap 22 and is closed by a cover 28. By removing the ca and cover 28., the pi e .24 may be swabbe out with a wire 'brus or other cleaning device.

The sludge level is usually at the same elevation as the abutments 14 and to maintain this level the slud 1s umped out throu h the pi s 24 an 27. The level of the e uent or iquid which rises and passes out of 'the' tank is controlled by the weirs ,used for sand and 20. As before stated the gas rises in the hood or transition chamber and passes up into the as chamber. Scum forms on top of the e uent in the gaschamber and frequently becomes so heavy as to hold back the gas, with disastrous results. To over come this a screen 29 is secured in end of the transition chamber at the bottom of the gas chamber (F ig. 3). This screen may be formed of a coarse mesh, such as is gravel screens or of any other foraminous material. The function of the screen is to retard the upward passage of the particles and to break up scum formations so that the gas will have a free upward passage.

The cover formed by the plates 21 traps the as which rises into the cap 22 from whicr it is conducted by a pipe 30. The eflluent flowing over the weirs 20 passes into a mechanical aerator 31 (Fig. 7 from which it flbws through a sluice 32 into a clarifier, such as is shown in my co-pending application Serial No. 23,442, filed April 16, 1925. In the house 34- of the clarifier I install a suitable water heater 35 preferably of the coil t pe. A watersupply pipe 36 leads to the eater and the gas pipe 30 also extends to the heater for supplying fuel for theoperation of said heater. A hot water pipe 37 leads from the heater to the tank 10 and a cold Water return pipe 38 leads from the tank to the heater.

In the gas pipe 30 is connected a trap consisting of a receptacle39 (Fig. 4) partially filled with water.. This trap has a release valve 40 of suitable construction mounted on its top and set to release the gas at a redetermined pressure. The pipe 30 is ent down at 41 to enter the trap below its water level and leaves said trap above its water level at 42. .A. water gravity feed pipe has a goose neck 44 entering the bottom of the receptacle. I

The water in the trap will be maintained atthe same level as the pipe 43. Should the gas explode or i mite between the trap and the heater 35 t e water would check its passage back to the tank 10 and the valve 40 would release the excessive pressure.

The hot water supply ipe 37 is connected to a vertical pipe 45 leading down to a coil immersed in the tank. The coil comprises pipes 47 extending along the sides and across the ends of the tank and running continuously downward to a bottom pipe 4-8 extending along the center of the bottom of the tank and connected to a riser 49. The riser is connected to the return pipe 3.

It will be seen that by placing a pump 50 in the return pipe 38 the hot waterfrom -'tl1e heater 35 iscirculated through the coil thus heating the slud e and raising its temperature so that its Iaiological activity is greatly increased and accelerated, thereby the upper Various changes in the size and shape of the different parts, as well as modifications and alterations may be made within the scope of the appended claims.

that I claim, is:

1. A sewage purification tank having longitudinal abutments on each side, longitudinal septums inclining upwardly from the abutments, a gas accumulating chamber above the septums extending longitudinally of the tank, sludge removing pipes extending to the bottom of the tank, a cover for the gas chamber, a cap on the cover, and a gas conductor leading from the cap.

2. A sewage purification tank havin 1ongitudinal abutments on each side, ongitudmal septums inclining upwardly from the abutments, a gas accumulating chamber above the septums extending longitudinall of the tank, sludge removing pipes extend ing to the bottom of the tank,a cover for the gas chamber, a cap on the cover, a gas conuctor leading from the cap, fluid circulating pipes in the tank below the septums and means for supplying a hot, fluid to said pipes.

3. In a sewage purifying tank, a sludge chamber in the bottom of the tank, a hood 1n the upper portion of the tank, bafies under the edges ofthe hood, a gas accumulating chamber above the hood extending longitudinally of the tank, a cover for said gas chamber extending longitudinally of the tank, and a cap on and above said cover.

4. In a sewage bottom of the tank, a hood in the up er portion of the tank, bafiles under the e ges of the hood, a gas accumulating chamber above the hood, a cover for said chamber, at ca removably mounted on said cover, and slu ge removing ipes having extensions communicating witli said cap.

5. In a sewage disposal fication tank having a sludge chamber at its bottom, a hood over the sludge chamber, a gas chamber connected with the top of the cod, a cover over the gas chamber,- a heatchamber in the ing coil in the sludge chamber, a water heatplant, a puripurifying tanlr,- a sludge ing from the tank to the heater, a oirculat- 7. In a sewage disposal plant, a purifica- 15 in coil in the sludge chamber connected to tion tank having a longitudinal sludge said circulating and return pipes. chamber at its bottom, a hood over the 6. A sewage purification tank having lonsludge chamber extending longitudinally 6 gitudinal abutments on each side, longithereof, a gas chamber above and contigutudinal septuins inclining upwardly from oils to the top of the hood, a cover closing Q the abutments, a gas accumulating chamber the top of the gas chamber and extending extending longitudinally of and over the longitudinally of the tank, a heating coil in septums, sludge removing pipes extending tothe sludge chamber, and means at the level the bottom of the tank, a cover for the gas of the sludge for breaking up scum formachamber extending longitudinally of the tions. 25 tank, a cap on the cover, a gas conductor In testimony whereof I afiix my signaleading-from the cap, and an exhauster conture.- nected in the gas conductor. HENRY L. THACKWELL. 

